The present invention relates to an improved device for controlling the locking and unlocking movements of a rotary disk, in a rotary table workpiece processing apparatus.
The invention also relates to an apparatus or machine including such an improved device.
The field of the invention is that of the machines including devices for locking and unlocking a rotary disk such as, for example, the rotary table of a transfer machine, a rotary-table conveyor, a revolver turret and the like in which, after the rotation, the locking of the rotary disk is performed by means of a ring gear coupling (for example of the HIRT type).
Are already known in the prior art machines of the above mentioned type, in which the control of the locking and unlocking movements of the rotary disk is performed by a ball recirculating screw and nut assembly which, on a side, operates on the rotary disk and, on the other side, is rotatively driven by a specifically designed motor-reducing unit.
Thus, as the screw is rotatively operated, the rotary disk is axially driven, with mutual approaching and withdrawing movements between corresponding ring gears, to provide, respectively, the locked and unlocked condition of said rotary disk.
In prior constructions of the above disclosed type, the axial force for mutually engaging the ring gears, correspondingly to the rotary disk locking operation, is fully or substantially fully provided by the ball recirculating screw and nut assembly.
Moreover, as the rotary disk has a vertical axis, to the preceding stresses, the weight of the rotary disk is also added, which, consequently, further stresses the mentioned screw and nut driving assembly.
As a direct consequence of the above disclosed drawbacks, in prior machines of the above mentioned type, the locking and unlocking speed of the rotary disk decreases with an increase of the rotary disk mass itself.
Furthermore, since the engagement force between the ring gears is fixed and determined by the driving assembly operating the screw and screw nut assembly, this effort may be insufficient as the masses to be driven are comparatively large and, anyhow, in machining operations requiring a maximum locking force by the rotary disk.